1. Field of the Invention
The present invention relates to a picture searching apparatus and, more particularly, to a picture searching apparatus capable of efficiently detecting a short shot inserted in video without any error.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 9-284667 discloses a subliminal picture processor for determining subliminal pictures included in pictures. The subliminal picture processor stores therein sequential image data on n images per image, compares the stored image data on the n images with latest input image data, and then, judges whether or not the stored image data is the same as the latest input image data. The subliminal picture processor determines that if data stored before the data which is judged to be the data on the same image is data which is judged to be data on a different image, images below n frames having image different from images on the preceding and following images are images of subliminal pictures.
FIG. 10 is a block diagram illustrating such the subliminal picture processor. An n images comparing section 52 compares sequential image data of n images output from an n images storage section 50 with latest input image data output from a latest image input section 51, and then, a different image determining section 53 determines whether both of the image data are the same as or different from each other. A subliminal picture determining section 54 determines subliminal pictures based on the determination result by the different image determining section 53. Finally, a subliminal picture removing section 55 removes the image data which is determined as the image data on the subliminal pictures.
In this manner, a conventional technique of detecting a short shot consisting of one frame or several frames inserted in sequential video is to detect the short shot based on the determination whether the latest input image is merely the same as or different from the already input n images.
However, the technique disclosed in Japanese Patent Application Laid-Open No. 9-284667 is to determine the short shot merely based on the comparison result of the latest input image with the already input n images, thereby raising a problem that the short shot inserted in high motion video may be detected with an error, although the short shot inserted in low motion video can be excellently detected.
For example, if motion of an image is not sequential even in the case of one and the same shot, only a part of the image included in one and the same shot may be possibly different from an input image. Therefore, there is a possibility of erroneous detection that the part of the image is a short shot (i.e., a subliminal picture). And, even if motion of video is sequential, it is determined that the latest input image is different from a previous image relatively apart from the latest input image, thereby leading to a possibility that a part of the different image may be erroneously detected as a short shot (i.e., a subliminal picture).